Assessment of Anomalous Propagation Conditions in Ondo City, South Western Nigeria for Microwave Applications

Abstract

Recent results of the in-situ measurement of radio climatological parameters of pressure, temperature and relative humidity carried out to investigate the trends in propagation conditions over altitude of 100-m in Ondo city Nigeria are presented. The assessments have been based on the time series of average value of the radio refractivity on the season of the year, characterization of radio refractivity gradient and the impact of secondary radio climatic data on terrestrial line of sight link design in Ondo city. We have used concurrent measurement of pressure, relative humidity and temperature for the period between 2017 and 2018. The results obtained confirmed the assertion that radio refractivity values are higher during the wet season months when compared with the dry season months. Yearly variation shows that the values of refractivity in the year 2018 are much higher than ones obtained in the year 2017. Results of radio refractivity gradient also shows a considerably large negative N value of about 288 N-units/km for the month of October and the value later becomes less negative in the remaining months of the year. Average value of k-factor during the dry and wet seasons for the year under study is about 1.37 and 1.47 respectively. This implies that, for microwave propagation in the Ondo environ, the propagation condition could be largely super-refractive during these seasons. A good relation also exists between Geoclimatic factor and season of the year. The overall will assist in achieving optimum performance of digital terrestrial point to point links in Ondo city.

Keywords: Propagation behavior, Time series analysis, Refractivity gradient, k-factor, Geoclimatic factor

DOI: 10.7176/JEES/9-4-07

Publication date: April 30^th 2019